JPH0319452A - label conversion circuit - Google Patents

Abstract

PURPOSE:To reduce the storage capacity of a label conversion table by converting an in-switch call identification number combining plural reference number bit strings resulting from dividing a bit string of a call identifier included in a header part into plural numbers and from converting them into the output terminal number of a switch and a new call identifier. CONSTITUTION:Call identifiers I1, I2 decomposed into N and M bits are converted into reference numbers r1, r2 respectively by using the identifiers as read addresses to index conversion tables 103, 104. Then a numeral r1+r2 being the combination of the numbers r1, r2 is used as a readout address to index a conversion table 105, thereby obtaining new call identifiers (I1, I2) and an output terminal number (DA). An incoming terminal number (SA) depends definitely on the line physical position, it is added to the header part of the cell or the header part is converted to form an in-switch cell. Since the conversion table is divided and subjected to hierarchy processing, the memory capacity is reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a digital or secondary switch, and in particular, transmits communication information using fixed-length packets (hereinafter referred to as "cells") consisting of a header section and an information section. The present invention relates to the configuration of a label conversion circuit that rearranges the contents of a header section in a self-routing type switch that exchanges calls, and a reference number assignment circuit that allocates a reference number for identifying calls within the switch.

[Conventional technology]

A typical conventional example is the Institute of Electronics, Information and Communication Engineers Technical Report (Switching System Study Group) SSE88-29 “Wideband I
``Prototype of ATM replacement machine for SDN'' (Kayu, Hatsukano, Shimoe.
There is an exchange shown in Murakami). The label conversion method is shown in Figure 3 of the above document, and according to it, a label conversion table is placed in front of the switch, and this conversion table is drawn using the call identifier of the input cell as an address.
This is a precept #1 that prays for routing information within the switch and a new call identifier. The contents of the label conversion table are omitted by sending data from the control system of the exchange at the time of call setup.

[Problem to be solved by the invention]

The conventional technique described above has a problem in that a large-capacity label conversion table is required. The call identifier must have a bit length with sufficient margin for the amount of communication, and there are cases where it is necessary to identify the path, which is the management unit of the transmission path, and the line, which corresponds to the call identifier. Therefore, the bit length is considered to be 20 bits or more. Therefore, the memory used as the conversion table requires only 2 addresses.
2°, so the number of 10 Mbits to several 100 Mbits per line
A capacity of M bits is required. Although memory is becoming increasingly highly integrated, this is an unrealistic value.

An object of the present invention is to provide a label conversion circuit that requires a relatively small amount of storage space for a label conversion table. Another object of the present invention is to provide a circuit with reference numeral 1Il necessary for realizing this label conversion circuit.

[Means to solve the problem]

The basic idea for achieving the above purpose is to decompose the call identifier and use multiple conversion tables so that one table can be realized with a single chip memory element, and to layer the conversion tables and create layers. There is a need to compress the address space when moving.

Specific measures are described below.

First, in order to achieve the first objective above, a plurality of conversion tables are provided that divide the bit string of the call identifier included in the header part into a plurality of parts and convert each divided part into a corresponding reference number, and We devised a label conversion circuit that has a conversion table that converts an internal switch call identification number, which is a combination of number bit strings, into a switch output terminal number and a new call identification number.

In addition, in order to avoid any inconvenience to the circuit operation even if a signal cell used for communication of a sign for exchange control is input to the label conversion circuit, cell type information included in the header section is detected, means for detecting whether the cell is a signaling cell for switching control; means for not converting a call identifier if the cell is a signaling cell; and transmitting the contents of the cell to a control mechanism section of the exchange. We have provided means to do so.

Next, in order to achieve the above second objective, the signal cell is used as input information, the bit string of the call identifier included in the header part of the signal cell is divided into a plurality of parts, and each of the divided parts is given a reference number corresponding to each. We devised a reference number assignment circuit with multiple conversion tables to convert into .

Furthermore, in order to minimize the storage capacity of the conversion table, the reference number allocation circuit detects that the contents of the conversion table for converting divided call identifiers into reference numbers are a specific bit pattern (for example, all zeros). means for writing a new reference number in the conversion table when the comparison result is a specific bit pattern; and writing the bit pattern as an address when the comparison result is not the specific bit pattern; and a reference number management table that can be read, a means for detecting whether or not the content of the management table is zero, and rewriting the bit pattern in the conversion table to a specific bit pattern if it is zero; A reference number assignment circuit has been devised that has means for increasing or decreasing the contents of a management table based on signal type information included in a signal cell.

[Effect]

In the information communication phase, the plurality of conversion tables of the label conversion circuit convert the bit strings of call identifiers extracted from the information communication cell and divided into reference numbers each having a smaller number of digits.

A call is uniquely identified using a bit string that combines these multiple reference numbers. The bit length of this bit string may be any value that can express a value with sufficient margin for the number of calls simultaneously communicated on one line. Therefore, this conversion table serves to reduce the bit length by converting the call identifier to the #R# number, thereby reducing the address space required for call identification.

The reference number assignment circuit assigns signaling cells,
The call identifier bit string contained in the call identifier is decomposed and converted into a reference number. The decomposed bit string may have the same value as the bit string obtained by decomposing the other 0 call identifier, and in this case, the same reference number is assigned. However, when the same reference number is assigned, a separately provided reference number management table stores whether that reference number has been used {gJ times. Since the bit length required for this storage is even smaller than the bit length of the reference number itself, the amount of memory required for the entire table can be reduced.

[″!A example] Embodiments of the present invention will be described below with reference to the drawings.

First, FIG. 2 is a schematic block diagram of a configuration example of a self-routing type exchange Cv. This exchange accommodates t lines and performs cell switching using a self-routing switch 300. The line handling unit (incoming line side) 100 and the line handling unit (outgoing side) 200 are circuits provided for each box. Of these, 10 of the mouth line correspondence departments (people & 14lI)
0 is connected to the switch, one incoming line is connected as an input, and the input terminal of the switch is connected as a force. This error response unit 100 has label conversion functions such as changing call identifiers of input cells and adding intra-switch routing information. On the other hand, line support section (outgoing line {all) 20
0 is placed after the switch, one of the outputs from the switch is connected as an input, and the output line is connected as an output.

This line handling unit 200 receives the signal cell from the control mechanism 400 and converts the conversion table of the line handling unit (input side) l00 to 1! Change F! Has II'@. control mechanism capital 4
00, one of the outputs of the switch is connected as an input, and one of the inputs of the switch is connected as an output.

Next, various cell formats are shown in FIG.

Here, as an example, the call identifier is Il. Assume that it is decomposed into two parts, I2. Il. I2 may be something meaningful, such as a path identifier or a line identifier, or it may simply be a bit string separated.

In the following description, the symbols shown in FIG. 5 may be used unless otherwise specified.

The call setup diagram of the self-routing switch shown in Figure 2
．． - In the system, a signal cell carrying call setting information (DN, II, 12, etc.)
0, where the output terminal number (DA') and input terminal number (SA) connected to the control mechanism section 400 are added and sent out. The control mechanism unit 400 allocates reference numbers (rl, r2) based on the reserved call identifiers (I1, I2) included in the call setting information of the signaling cell, and also assigns a new identifier to be used as a call identifier on the outgoing line. Ql', engineering 2! )
, the output terminal number (DA) of the switch, etc., and sends the signal cell containing this information to the line handling section (output side) 20.
Send it to 0. The line handling unit (outgoing line side) 200 transfers the above received information to the line handling unit (incoming line side) l00.
write to the conversion table. Here, line support section (incoming line I
I) 100 and the line corresponding section (output 1) III) 200 are actually integrated as shown in FIG.

In the information transfer phase, line support S (incoming line) 1
00 is subjected to label conversion, an output terminal number etc. are added, and the cell is sent to the self-routing switch 300.
sent to. After switching, this cell is output from the line corresponding section (output line side) 200, the A power terminal number, etc. are removed, and the cell is sent out to the output line.

FIG. 3 shows an example of the configuration of the control mechanism section 400.

A plurality of reference number assignment circuits 4l00 are provided corresponding to lines. Input signal cells are distributed by a distribution mechanism 4200 based on input terminal numbers (SA). Further, the output signal cells from each reference number assignment circuit 4100 are transmitted to the line concentrator 43
00, self-runing switch 300
sent to.

Next, details of the label conversion circuit will be explained using FIG.

First, the human line is input to the input register lot. and is connected to the output register 102 via the delay circuit 109.

Output lines Il and I2 are provided from the input register 101, and are connected to a conversion table 103 (TABl), respectively.
c), conversion table 104 (TAL32c)
is connected to the read address input of the . Also,
The II take-out line is also connected to the signal cell detection circuit 106. Conversion table 103. Each data output line of 104 is connected to a conversion table 105 (TAB3c).
is connected to the read address input of the . The data output line of conversion table 105 is connected to output register 102 via gate 107. gate 10
7 is connected to the output of the signal cell detection circuit 106. The output of the input terminal number setting circuit 108 is connected to the output register 102. The output of the output register 102 is connected to the input terminal of the self-routing switch 300.

On the other hand, one of the output terminals of the switch is connected to the person register 20.
1 and a delay circuit 205 to an output register 203. The manual register 201 is connected to various take-out lines or a transfer register 202 . Among the various output lines of the transfer register 202, the call identifier I1.
I2 to the write address inputs of translation tables 103 and 104 and the write address input of translation table 1050, respectively, with reference numbers rl. r2 are connected to data inputs of conversion tables 103 and 104, respectively. A new identifier (I
l'. I2') or switch output terminal number (D person)
etc. are connected to the data inputs of the conversion table 105. Note that the call identifier clearing circuit M204 is a circuit that converts the received and used signal cells into empty cells.

The operation of this label conversion circuit will be explained using FIG. 6. FIG. 6 shows how the conversion is performed using the conversion table. Call identifier II broken down into N bits and M bits
, I2 are read by referring to the conversion tables 103 and 104, respectively. It is converted to r2. Next, a new call identifier is created by referring to the conversion table 105 using the combination of rl and r2 (for example, if rl is the upper bit and r2 is the lower bit, it will be abbreviated as "rl+r2J"). (II, I2) and the output terminal number (DA) are obtained.The input terminal number (SA) is uniquely determined by the physical position of the line.

By adding these to the header part of the cell or converting the header part, it becomes an intra-switch cell. If the input cell is a signal cell, no conversion is performed and the terminal number connected to the control mechanism section is added as the output #r number.

When the above conversion method is adopted, the bit length of rl may be n, which is shorter than If, and the bit length of r2 may be m, which is shorter than f2. This is because so many calls are not set up on one line at a time that the bit length of the call identifier is fully used.

Here, we will give a concrete numerical example and compare it.

N = 12, M = 16. U=10 (bit)
In this case, when converting using the conventional method, that is, using one table, the result is 211"' x 12 + 16 + 10, which is approximately 1
It has a memory capacity of 0 Gbit. On the other hand, if n=m-8, it becomes 212×8+2” This value is currently available and is achievable.

Next, the reference number assignment circuit will be explained with reference to FIG. Distribution mechanism 4200 shown in FIG. 3 from the output terminal of the switch
The input line via is connected to input register 4101 and output register 4110. The extraction line for call setting information, etc. (signal information including call disconnection information, etc.) is converted to conversion table 4.
It is connected to the read address input of 1l1. At the same time, 11 parts of the above information are stored in the conversion table 41.
It is connected to the read address input of 02. The data output of the conversion table 4111 is output from the output register 411.
connected to 0. The data output of the conversion table 4l02 is connected to the register 4104 and the comparison circuit WI14103. Among the outputs of the comparator circuit, the output when the output is not O is the enable input of the register 4l04. On the other hand, the output when it is O is the output enable input of the reference number storage circuit 4106 (FIFO 1). The output of the register 4104 is sent to the reset circuit 4.
It is connected to output register 4110 via l12. In addition, the output is also sent to the reference number management table 410 at the same time.
5 readout address input and reference number storage circuit 410
It also serves as the input for 6. The data output of the reference number storage circuit 4106 is sent to the comparison circuit 4107! 1! It is continued. The output of the comparison circuit 4107 serves as the reset input of the reset circuit 41l2 and the input enable A of the reference number storage circuit 4106. From the input register 4101, take-out lines for call identifier part Jl and signal type K are connected to a signal type detection circuit 4109, and its output is connected to a data increment/decrement circuit 4108. The output of the data increment/decrement circuit 4108 is the reference number management table 4l0.
There are 5 data inputs.

Note that the circuit corresponding to J2, which is the remaining part of the call identifier, has the same configuration as the circuit corresponding to Jl, so the details will be omitted.

The operation of the above circuit is shown in FIG. Conversion tables are looked up at II and I2 included in the call setting information, respectively, to obtain cl and a2. (Only the %ll side will be explained below.)
If cl is a specific pattern, for example 0, then this II
is used for the first time, and at this time, rl is taken out as a new reference number from the reference number storage circuit and replaced with cl on the conversion table. On the other hand, if cl is not O, this II is already in use, so this C1
Look up the reference number management table using the value of . Then there is
The number of times this C1 is currently used is written as ql, and in the case of call setup, this value is further increased by one.

In case of call disconnection, decrease by one. If ql is 0, this means that all calls using rl have been disconnected, so rl is returned to the reference number storage circuit.

At the same time, the transfer to the output register is stopped.

From the call setting information (for example, dialed number: DN), a translation table (TRANS) is drawn to obtain new call identifiers II', I2' and output terminal number DA.

The contents of this edge table are set by a control system (not shown) during a series of call setting procedures.

The conversion table of this circuit also has the same configuration as the label conversion table described above, and by adopting this configuration, memory capacity can be reduced. Note that the reference number management table has a bit width that is even less than n and m, and the number of words is 2n.
The required amount of memory is extremely small since it is only 2m long.

〔Effect of the invention〕

As described above, the present invention divides and hierarchizes the conversion table in the label conversion circuit, so it requires much less memory than using the original conversion table. A-ability can be achieved.

Furthermore, since the reference number allocation circuit 1, which is effective in hierarchizing the conversion table, similarly divides and hierarchizes the conversion table, the memory can be reduced to the same extent as in the label conversion circuit. As an example, C is approximately 10G in the conventional method.
When a bit of memory capacity is required for line support,
Equivalent functionality can be achieved with a memory capacity of 2.5 Mbit, which is about 1/4000th of this.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a label conversion circuit which is an embodiment of the present invention, Fig. 2 is a diagram of the structure of an exchange using the label conversion circuit of Fig. 1, and Fig. 3 is a part of a WJz diagram. 4 is a block diagram of a reference number assignment circuit which is a central embodiment of the present invention; FIG. 5 is a structural diagram of a cell handled by the exchange of this embodiment; and FIG. Operation explanatory diagram of figure 7
The figure is an explanatory diagram of the operation of FIG. 4. 100...Line corresponding section (incoming line side) 200...Line corresponding section (outgoing line gl!l) 300...Self-norting switch 400...Control mechanism section 103, 104, 105...Conversion table 410
2...Conversion table 4105...Reference number management table 4l06
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·three! ! , ) k 岑辑辑田路郎 6fig. (Residence) (C) [TAB C] [TAB 3C] n (<11) I-N 10M + U→ Force 5fig. 1- M @←N@ I- Bat→ToNto υ→←U→ +MmI−N−+ Younger brother 7 figure (OL) [TA[l'−n(<N) [FIFD [M～G 1koh i(<n) −1 ( b) [TAB 2sl [Response G2] [TRAIIS] +-gate+N middle υ state

Claims (1)

[Claims] 1. In a self-routing switch that exchanges communication information using fixed-length packets (hereinafter referred to as "cells") consisting of a header section and an information section, a bit string of a call identifier included in the header section. is divided into a plurality of parts, and each of the divided bit strings is converted into a corresponding reference number using a plurality of conversion tables. 1. A label conversion circuit suitable for a self-routing switch, comprising a conversion table for converting into a call identifier. 2. In the label conversion circuit according to claim 1, means for detecting cell type information included in the header portion and detecting whether or not the cell is a signal cell for switching control, and if the cell is a signal cell, 1. A label conversion circuit comprising means for not converting a call identifier and means for transmitting the contents of the cell to a control mechanism section of an exchange. 3. In the label conversion circuit of claim 2, when the cell type is a signal cell, the content of the signal cell is transferred to the control mechanism section of the exchange by setting the output terminal number added to the cell as the input terminal number of the control mechanism section. A label conversion circuit characterized in that it transmits information to the user. 4. In a self-routing switch that exchanges communication information using cells consisting of a header section and an information section, the bit string of the call identifier included in the header section is divided into two, and one of the divided bit strings is used as the corresponding reference. It is characterized by having a conversion table for converting into a number, and a conversion table for converting an internal switch call identification number composed of the other divided bit string and the reference number bit string into an output terminal number of the switch and a new call identifier. A label conversion circuit suitable for self-routing switches. 5. In a self-routing type switch that exchanges communication information using cells consisting of a header part and an information part, a signal cell used for communication of signals for switching control is used as input information, and a call included in the signal cell is used as input information. 1. A reference number assignment circuit comprising a plurality of conversion tables for dividing a bit string of an identifier into a plurality of parts and converting each divided bit string into a corresponding reference number. 6. The reference number assignment circuit according to claim 5, further comprising: a comparison circuit that detects that the contents of the conversion table for converting the divided call identifier into the reference number is a specific bit pattern; A means for writing a new reference number into the conversion table at a certain time, a reference number management table capable of writing and reading the bit pattern as an address when the comparison result is not a specific bit pattern, and the contents of the management table. means for detecting whether or not is zero and rewriting the bit pattern in the conversion table to a specific bit pattern when it is zero; A reference number assignment circuit characterized in that it has means for increasing or decreasing.